package com.github.niefy.common.utils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.util.StringUtils;

import javax.servlet.http.HttpServletRequest;
/**
 * IP地址
 *
 * @author Mark sunlightcs@gmail.com
 */
public class IPUtils {
  private static final String UNKNOWN = "unknown";
  private static final Logger logger = LoggerFactory.getLogger(IPUtils.class);
  /**
   * 获取IP地址
   * 使用Nginx等反向代理软件， 则不能通过request.getRemoteAddr()获取IP地址
   * 如果使用了多级反向代理的话，X-Forwarded-For的值并不止一个，而是一串IP地址，X-Forwarded-For中第一个非unknown的有效IP字符串，则为真实IP地址
   */
  public static String getIpAddr(HttpServletRequest request) {
    String ip = null;
    try {
      ip = request.getHeader("x-forwarded-for");
      if (!StringUtils.hasText(ip) || UNKNOWN.equalsIgnoreCase(ip)) {
        ip = request.getHeader("Proxy-Client-IP");
      }
      if (!StringUtils.hasText(ip) || ip.length() == 0 || UNKNOWN.equalsIgnoreCase(ip)) {
        ip = request.getHeader("WL-Proxy-Client-IP");
      }
      if (!StringUtils.hasText(ip) || UNKNOWN.equalsIgnoreCase(ip)) {
        ip = request.getHeader("HTTP_CLIENT_IP");
      }
      if (!StringUtils.hasText(ip) || UNKNOWN.equalsIgnoreCase(ip)) {
        ip = request.getHeader("HTTP_X_FORWARDED_FOR");
      }
      if (!StringUtils.hasText(ip) || UNKNOWN.equalsIgnoreCase(ip)) {
        ip = request.getRemoteAddr();
      }
    }
    catch (Exception e) {
      logger.error("IPUtils ERROR ", e);
    }
    return ip;
  }
}
